Virtual Bus Simulation

Testing ECUs and their communication on a PC

No ECU prototypes or additional hardware necessary due to virtual ECUs

Independent of real-time limitations

Use of existing communication matrices and restbus configurations

Reuse of test and experiment environments

​The Challenge: Developing and Validating Distributed Functions in an ECU Network
Some functionalities involve multiple software components (SWCs) that are distributed over various ECUs. These ECUs communicate via bus networks. In order to test these functionalities thoroughly, the complete system, including the communication between the ECUs, has to be simulated. Ideally, these tests should take place as early as possible during the development.

The Idea: Bus Simulation in Early Development Stages
Early tests of the bus communication are possible by using the PC-based simulation platform dSPACE VEOS. Since virtual ECUs (V-ECUs) are used, the only hardware needed is a standard PC. No further ECU hardware prototypes are required. During ECU software development, the necessary V-ECUs are generated on the basis of an existing communication matrix that defines inter-ECU communication. For each new software iteration, the V-ECUs can be updated easily, ensuring that the communication tests are always up to date. Because V-ECUs and VEOS are purely software-based, they make the simulation independent of real-time limitations. The restbus simulation needed for testing the whole system communication is defined on the basis of the same communication matrix as the V-ECU. A detailed bus monitoring down to the signal level is available for the virtual bus simulation, just as for real-time simulation.

This virtual bus communication simulation lets function developers find and fix errors long before the hardware-in-the-loop (HIL) simulation takes place, thus saving valuable time at the HIL simulator. Additionally, all artifacts created for communication tests with VEOS, such as tests scripts, bus and other configurations, can be reused for the HIL tests, saving further configuration efforts.

One Example: Early Validation of a Comfort ECU
An existing comfort functionality is extended by a new component that runs on a comfort ECU in the rear of the car. This ECU communicates with the main comfort ECU at the front of the vehicle via CAN. The main ECU has already been tested in the form of a V-ECU. The restbus simulation configuration was generated with the Bus Manager.

As soon as the new component is available, e.g., as a Simulink® model, it is used to generate a V-ECU. The bus configuration of the main ECU can be reused, which makes setting up the virtual bus simulation effortless. Because the same communication matrix is used for defining the communication between the V-ECUs and configuring the restbus simulation, the two parts interact seamlessly and do not have to be modified at all.

Later in the test process, the already tested restbus simulation can be reused for HIL tests, including the configurations, test layouts and monitorings created for the virtual bus simulation.